The Powerful and Safe Bet for the Data Center Footprint Challenge
Data center real estate is always at a premium. Every square foot used for servers and storage can generate more revenue. So reducing the power infrastructure footprint can boost revenue, impact safety and also has implications for backup capacity. We call this the Footprint Challenge.
For decades, the industry has relied on lead-acid backup batteries that have a large, heavy footprint. Some data center operators are looking to lithium-ion batteries for their smaller footprint and lighter weight. However, concerns over safety with lithium-ion energy storage systems have driven additional placement spacing requirements by the NFPA 855 standard for the Installation of Stationary Energy Storage Systems, requirements that can effectively cancel out the footprint savings of lithium-ion systems.
Safety measures eat up footprint
Energy storage system footprint is largely determined by battery power density. Yet a battery must deliver energy safely to realize power density-driven footprint reduction and savings. Without safe energy delivery, the authorities having jurisdiction (AHJ) have no choice but to enforce placement restrictions and other safety measures such as enhanced fire suppression that negate any footprint advantages.
High power density batteries that can operate safely are the right step to overcoming The Footprint Challenge. Understanding that lithium-ion batteries are not the right answer, let’s look at why lead-acid batteries can’t meet the challenge, then meet the type of battery that does—nickel-zinc (NiZn).
What you need is a power battery
To see why lead-acid batteries are a dead-end, you should know the fundamental differences between an “energy” battery and a “power” battery. If you are in an electric vehicle (EV), energy density is most important: being able to discharge the energy out of the battery at a lower rate for as long as possible to limit range anxiety. Billions of dollars are being spent globally to increase the energy density of EV batteries.
This won’t help your data center Footprint Challenge!
Data center backup batteries must discharge the battery at a high rate for a short period of time to maintain operations while long term power systems such as generators spin up. Battery power density is what delivers high rate discharge, ideally in a relatively small footprint.
A lead-acid battery is an “energy” battery, meaning the data center industry has been using the wrong tool for the job for a long time. NiZn batteries are “power” batteries that give you an edge in the Footprint Challenge.
Power density with inherent safety
With about twice the power density of lead-acid batteries, NiZn batteries are well suited to data center backup power applications. Backup systems available today based on nickel-zinc batteries offer the industry’s smallest footprint and lightest weight per watt in solutions ranging from 1 kW to 2MW. That’s the magic of power density.
Unlike lithium-ion, NiZn technology has no inherent safety issues. To demonstrate this, we turn to the test method titled UL 9540A, Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems. This UL test method is referenced in the NFPA 855 standard to assist AHJ’s in interpreting and enforcing NFPA 855 for different battery chemistries.Underwriters Laboratories tested ZincFive’s NiZn batteries at the “cell level”, the most fundamental level in the test method. ZincFive’sNiZn batteries did not exhibit thermal runaway in any of the five arduous and destructive test types that comprise the UL 9540A test method.
A high power density battery that delivers energy safely – it looks like we found a winner in the Footprint Challenge!
Now many battery manufacturers have had their batteries tested to the UL 9540A test method. You should understand that the UL 9540A test method allows different levels of testing in which a manufacturer can include a battery management system (BMS) and other safety measures in order to complete the tests without exhibiting thermal runaway. But make sure you ask what level of UL 9540A testing they used. Wouldn’t it be better to start with a power-dense battery chemistry that is fundamentally safe at the cell level?